Do you think the high crime rates of the 70s, 80s and 90s in America had anything to do with the trauma the Vietnam War caused? The average age of a Vietnam War vet was 19 and even today they’re only about 65 years old, so the trauma would still have effected people born as late as the 2000s in a direct way, for example fathers who fought in the war taking their pain out on their children.
Not only that but also the drinking and other ways of coping with the horrible memories I could see increasing the crime rate by exacerbating drug trading and alcohol abuse.